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Todayโs path rounds are on the canine ๐๐ฌ๐จ๐ฉ๐ก๐๐ ๐๐๐ฅ ๐ฐ๐จ๐ซ๐ฆ, ๐๐ฉ๐ข๐ซ๐จ๐๐๐ซ๐๐ ๐ฅ๐ฎ๐ฉ๐ข!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฉ๐ข๐ซ๐จ๐๐๐ซ๐๐ ๐ฅ๐ฎ๐ฉ๐ข is a type of ๐ง๐๐ฆ๐๐ญ๐จ๐๐ (round worm) that invades into the esophagus, forming a ๐ ๐ซ๐๐ง๐ฎ๐ฅ๐จ๐ฆ๐, a round nodule of inflammation.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This parasite primarily affects Canids like dogs, however it can infect other carnivores as well.
๐๐จ๐ฐ ๐๐จ ๐๐ง๐ข๐ฆ๐๐ฅ๐ฌ ๐ ๐๐ญ ๐ข๐ง๐๐๐๐ญ๐๐?
Dogs will eat small creatures like dung beetles, rodents, poultry or reptiles which contain the larvae of the worm. From there, the larvae gain access to the stomach wall and invade into the ๐ฆ๐ฎ๐๐จ๐ฌ๐ (stomach lining). Once in the stomach wall, they find an artery and move along them to the ๐๐จ๐ซ๐ญ๐ (major vessel off the heart). After further developing, they burrow out through the aorta wall into the adjacent esophagus, where the now adult worms form granulomas to live in. Now that they have a nice house, the female worms will burrow their tails out of the granuloma to deposit eggs into the gastrointestinal tract for excretion in the animalโs feces. The small creatures ingest the feces and get infected with larvae, and the cycle continues!
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Sometimes the larvae end up in unusual sites, like the bladder, spinal cord and kidney, in their attempts to reach the aorta. This can cause formation of granulomas in these areas, which can cause all kinds of issues. For example, if the granulomas form in the spine, boney projections can form that pinch the spinal cord and cause gait issues like wobbling or collapsing.
The granulomas in the esophagus can also be problematic, as they are prone to developing into tumours. This is because the inflammation caused by the worms stimulates the surrounding cells to become ๐ซ๐๐๐๐ญ๐ข๐ฏ๐ in an attempt to heal tissue damage. These chronically stimulated cells may eventually develop changes in their DNA that allows them to form tumours. If these tumours grow sufficiently large, they can even cause ๐ก๐ฒ๐ฉ๐๐ซ๐ญ๐ซ๐จ๐ฉ๐ก๐ข๐ ๐จ๐ฌ๐ญ๐๐จ๐ฉ๐๐ญ๐ก๐ฒ (see our previous post on this condition!).
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Diagnosis is usually based on a ๐๐๐๐๐ฅ ๐๐ฅ๐จ๐ญ๐๐ญ๐ข๐จ๐ง, where the feces is dissolved in a high sugar fluid, which lets the eggs float to the surface. Another option is ๐ ๐๐ฌ๐ญ๐ซ๐จ๐ฌ๐๐จ๐ฉ๐ฒ, where a camera is introduced down the esophagus, to visualize the granulomas directly.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
Typically this disease is treated with a course of ๐๐๐ฐ๐จ๐ซ๐ฆ๐๐ซ๐ฌ which directly kill the worms. However this treatment is usually not very successful because the granuloma around the worms protects them from drugs in the bloodstream. To prevent infection, dogs should be supervised to keep them from ingesting small creatures that may carry the larvae.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-5) Examples of esophageal granulomas, some with worms poking out 
6-7) A granuloma before and after opening
8 ) An example where the worms invaded into the ๐ฉ๐ฅ๐๐ฎ๐ซ๐ (lining of the thorax) instead of the esophagus.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Photos 1-8 courtesy of Noahโs Arkive.
